The Federal Communications Commission (FCC) has allotted a spectrum of bandwidth in the 60 GHz frequency range (57 to 64 GHz). The Wireless Gigabit Alliance (WiGig) is targeting the standardization of this frequency band that will support data transmission rates up to 7 Gbps. Integrated circuits, formed in semiconductor die, offer high frequency operation in this millimeter wavelength range of frequencies. Some of these integrated circuits utilize Complementary Metal Oxide Semiconductor (CMOS), Silicon-Germanium (SiGe) or GaAs (Gallium Arsenide) technology to form the dice in these designs. At 60 GHz, the interface issues between the LNA and the mixer are presented.
CMOS (Complementary Metal Oxide Semiconductor) is the primary technology used to construct integrated circuits. N-channel devices and P-channel devices (MOS device) are used in this technology which uses fine line technology to consistently reduce the channel length of the MOS devices. Current channel lengths are 40 nm, the power supply of VDD equals 1.2V and the number of layers of metal levels can be 8 or more.
Cost is a driving force in electronic products. Integration of circuit has allowed many more devices into the die. In addition, massive computation is typically requires when operating wireless systems. This has forced analog designers to introduce their circuit techniques into 8 layer metal CMOS processes more geared for digital logic manipulation rather than analog functions. The design of high speed analog circuits (60 GHz) in the 8 layer 40 nm CMOS process is a difficult task that requires innovation, careful design and analysis.
Conventional techniques in high frequency circuit design can unnecessarily waste energy. Any technology being pushed to the limit, as in the design of 60 GHz receiver frond-ends that includes an LNA (Low Noise Amplifier) and mixer, makes these energy losses more pronounced. These losses influence target objectives and can cause the chip or die to fail meeting the specifications. New circuit techniques are required to reduce these energy losses and allow the circuit to achieve 60 Ghz operation in the WiGig specification.